When the season started, Sunday’s game between the defending Super Bowl champion Packers and the Chargers appeared to be a marquee matchup, perhaps even a Super Bowl preview.

Now, the Chargers are desperate for a win after two startling road flops. An upset of the undefeated Packers could save their season and, for the time being, appease the normally placid fans who are incensed with the Chargers‘ performance. Most of the ire is aimed at coach Norv Turner and general manager A.J. Smith.

The Packers are 7-0 behind quarterback Aaron Rodgers, whose offseason home is in Del Mar, just north of San Diego. The Chargers are 4-3 and in a three-way tie in the AFC West after their Monday night debacle at Kansas City, which followed a collapse against the New York Jets.

“We’ve got to move forward in a hurry,” said quarterback Philip Rivers, who keeps throwing the ball to the other guys and has fans wondering if his ineffectiveness is due to an undisclosed injury. “We’ve got a team that hasn’t lost a game since last December rolling in here. There’s no time to dwell on the past because we can’t change it. But we can have an impact on this game this weekend. It’s about as exciting as it gets, playing a team that hasn’t lost this season, won it all last year.”

The contrast between the franchises is as different as a sunny SoCal beach and the frozen Wisconsin landscape.

Rodgers has one Super Bowl ring. Rivers has none. The Packers have four Lombardi trophies to keep polished. The Bolts were blown out in their only Super Bowl appearance. Fans in Green Bay are dreaming about a perfect season. Chargers fans are simply hoping for a decisive victory over a good team.

Rodgers is confident and flinging the ball all over the place at record pace. Rivers, according to Turner, is pressing at times, as evidenced by his 11 interceptions and three lost fumbles, compared to seven TD passes.

Rivers doesn’t think he’s pressing, but his numbers suggest otherwise. Plus, there was his shocking fumbled snap in the final minute of regulation in a tie game at Kansas City Monday night, when the Chargers were driving for a sure score. Instead, they lost 23-20 in overtime. A week earlier, the Chargers blew an 11-point halftime lead and lost 27-21 to the Jets after botching a two-minute drill.

But the QB isn’t the only one playing poorly.

Veteran left tackle Marcus McNeill committed six penalties on Monday while trying to fend off Tamba Hali. They were among the 12 penalties for 105 yards, giving San Diego 25 penalties for 200 yards in two games.

Second-year running back Ryan Mathews whiffed again on a blitz pickup, lost another fumble and was hurt again. That’s been his MO since he was drafted as LaDainian Tomlinson’s heir apparent. Other than Eric Weddle’s five interceptions, the defense hasn’t had a big impact.

“Philip is a great quarterback _ everyone knows that. He’s obviously had some struggles this year but he’ll get through it,” Packers nose tackle B.J. Raji said. “Hopefully it won’t be against us. He’s a good player and he’ll bounce back. They’re one of those teams that has so many weapons. We’ll have to be ready to play some football. They might come out and chase that complete game.”

The Chargers had nine players on the injury report Wednesday, including guard Kris Dielman, who will miss his second game due to a concussion, and running back Curtis Brinkley, who likely will sit out due to a concussion sustained Monday night. Outside linebacker Shaun Phillips likely will sit again with a foot injury. Running back Mike Tolbert is expected to play after missing the Kansas City game.

Still, while the Chargers always keep the injury excuse within reach, the Packers proved last year that injuries can be overcome. They ended the season with 16 players on injured reserve, including six starters. During the Super Bowl victory against Pittsburgh, Charles Woodson was knocked out with a broken collarbone and Donald Driver with an ankle injury. A few other Packers were hurt in the Super Bowl but played through the injuries.